@preprocessor typescript

@{%
import { Expr } from "./parsed";
%}

expr -> term {% id %}

term -> term _ "+" _ factor
		{% ([left, _0, _1, _2, right]): Expr =>
			({ exprType: "binary", binaryType: "add", left, right }) %}
	| term _ "-" _ factor
		{% ([left, _0, _1, _2, right]): Expr =>
			({ exprType: "binary", binaryType: "subtract", left, right }) %}
	| factor {% id %}

factor -> factor _ "*" _ unary
		{% ([left, _0, _1, _2, right]): Expr =>
			({ exprType: "binary", binaryType: "multiply", left, right }) %}
	| factor _ "/" _ unary
		{% ([left, _0, _1, _2, right]): Expr =>
			({ exprType: "binary", binaryType: "divide", left, right }) %}
	| unary {% id %}

unary -> "+" _ unary
		{% ([_0, _1, subject]): Expr =>
			({ exprType: "unary", unaryType: "plus", subject }) %}
	| "-" _ unary
		{% ([_0, _1, subject]): Expr =>
			({ exprType: "unary", unaryType: "negate", subject }) %}
	| operand {% id %}

operand -> "(" _ expr _ ")" {% ([_0, _1, expr]): Expr => expr %}
	| [0-9]:+
		{% ([token]): Expr =>
			({ exprType: "int", value: parseInt(token.join("")) }) %}

_ -> __:?
__ -> ws:+

ws -> [ \t\r\n]